Process for the preparation of 1,1,1,3,3-pentafluoropropane and 1,1,1,2,3-pentafluoropropane

ABSTRACT

A process is disclosed for the manufacture of CF 3 CH 2 CHF 2  and CF 3 CHFCH 2 F. The process involves (a) reacting hydrogen fluoride, chlorine, and at least one halopropene of the formula CX 3 CCl═CClX (where each X is independently F or Cl) to produce a product including both CF 3 CCl 2 CClF 2  and CF 3 CClFCCl 2 F; (b) reacting CF 3 CCl 2 CClF 2  and CF 3 CClFCCl 2 F produced in (a) with hydrogen to produce a product including both CF 3 CH 2 CHF 2 , and CF 3 CHFCH 2 F; and (c) recovering CF 3 CH 2 CHF 2  and CF 3 CHFCH 2 F from the product produced in (b). In (a), the CF 3 CCl 2 CClF 2  and CF 3 CClFCCl 2 F are produced in the presence of a chlorofluorination catalyst including a ZnCr 2 O 4 /crystalline α-chromium oxide composition, a ZnCr 2 O 4 /crystalline α-chromium oxide composition which has been treated with a fluorinating agent, a zinc halide/α-chromium oxide composition and/or a zinc halide/α-chromium oxide composition which has been treated with a fluorinating agent.

FIELD OF THE INVENTION

This invention relates to the synthesis of 1,1,1,3,3-pentafluoro-propaneand 1,1,1,2,3-pentafluoropropane.

BACKGROUND

A number of chlorine-containing halocarbons are considered to bedetrimental toward the Earth's ozone layer. There is a world-wide effortto develop materials having lower ozone depletion potential that canserve as effective replacements. For example, the hydrofluorocarbon,1,1,1,2-tetrafluoroethane (HFC-134a) is being used as a replacement fordichlorodifluoromethane (CFC-12) in refrigeration systems. There is aneed for manufacturing processes that provide halogenated hydrocarbonsthat contain less chlorine or no chlorine. The production ofhydrofluorocarbons (i.e., compounds containing only carbon, hydrogen andfluorine), has been the subject of considerable interest to provideenvironmentally desirable products for use as solvents, blowing agents,refrigerants, cleaning agents, aerosol propellants, heat transfer media,dielectrics, fire extinguishants and power cycle working fluids. Forexample, 1,1,1,3,3-pentafluoropropane has utility as a blowing agent,and 1,1,1,2,3-pentafluoropropane has utility as a refrigerant and as anintermediate for producing fluoroolefins.

SUMMARY OF THE INVENTION

This invention provides a process for the manufacture of1,1,1,3,3-pentafluoropropane (HFC-245fa) and1,1,1,2,3-pentafluoropropane (HFC-245eb). The process comprises (a)reacting hydrogen fluoride (HF), chlorine (Cl₂), and at least onehalopropene of the formula CX₃CCl═CClX, wherein each X is independentlyselected from the group consisting of F and Cl, to produce a productcomprising CF₃CCl₂CClF₂ and CF₃CClFCCl₂F, wherein said CF₃CCl₂CClF₂ andCF₃CClFCCl₂F are produced in the presence of a chlorofluorinationcatalyst comprising at least one composition selected from the groupconsisting of (i) compositions comprising ZnCr₂O₄ and crystallineα-chromium oxide, (ii) compositions comprising a zinc halide andα-chromium oxide and (iii) compositions of (i) or (ii) which have beentreated with a fluorinating agent (e.g., anhydrous hydrogen fluoride);(b) reacting CF₃CCl₂CClF₂ and CF₃CClFCCl₂F produced in (a) with hydrogen(H₂), optionally in the presence of HF, to produce a product comprisingCF₃CH₂CHF₂ and CF₃CHFCH₂F; and (c) recovering CF₃CH₂CHF₂ and CF₃CHFCH₂Ffrom the product produced in (b).

DETAILED DESCRIPTION

This invention provides a process for the preparation of CF₃CH₂CHF₂(HFC-245fa) and CF₃CHFCH₂F (HFC-245eb). The HFC-245fa and HFC-245eb maybe recovered as individual products and/or as one or more mixtures ofthe two products.

In step (a) of the process of this invention, one or more halopropenecompounds CX₃CCl═CClX, wherein each X is independently selected from thegroup consisting of F and Cl, are reacted with chlorine (Cl₂) andhydrogen fluoride (HF) to produce a product mixture comprisingCF₃CCl₂CClF₂ (CFC-215aa) and CF₃CClFCCl₂F (CFC-215bb).

Accordingly, this invention provides a process for the preparation ofmixtures of CF₃CCl₂CClF₂ (CFC-215aa) and CF₃CClFCCl₂F (CFC-215bb) fromreadily available starting materials.

Suitable starting materials for the process of this invention include E-and Z-CF₃CCl═CClF (CFC-1214xb), CF₃CCl═CCl₂ (CFC-1213xa), CClF₂CCl═CCl₂(CFC-1212xa), CCl₂FCCl═CCl₂ (CFC-1211xa), and CCl₃CCl═CCl₂(hexachloropropene, HCP), or mixtures thereof.

Due to their availability, CF₃CCl═CCl₂ (CFC-1213xa) and CCl₃CCl═CCl₂(hexachloropropene, HCP) are the preferred starting materials for theprocess of the invention.

Preferably, the reaction of HF and Cl₂ with CX₃CCl═CClX is carried outin the vapor phase in a heated tubular reactor. A number of reactorconfigurations are possible, including vertical and horizontalorientation of the reactor and different modes of contacting thehalopropene starting material(s) with HF and chlorine. Preferably the HFand chlorine are substantially anhydrous. In one embodiment of step (a),the halopropene starting material(s) are fed to the reactor contactingthe chlorofluorination catalyst. The halopropene starting material(s)may be initially vaporized and fed to the first reaction zone asgas(es).

In another embodiment of step (a), the halopropene starting material(s)may be contacted with HF in a pre-reactor. The pre-reactor may be empty(i.e., unpacked), but is preferably filled with a suitable packing suchas Monel™ or Hastelloy™ nickel alloy turnings or wool, or other materialinert to HCl and HF which allows efficient mixing of CX₃CCl═CClX and HFvapor.

If the halopropene starting material(s) are fed to the pre-reactor asliquid(s), it is preferable for the pre-reactor to be orientedvertically with CX₃CCl═CClX entering the top of the reactor andpre-heated HF vapor introduced at the bottom of the reactor.

Suitable temperatures for the pre-reactor are within the range of fromabout 80° C. to about 250° C., preferably from about 100° C. to about200° C. Under these conditions, for example, hexachloropropene isconverted to a mixture containing predominantly CFC-1213xa. The startingmaterial feed rate is determined by the length and diameter of thereactor, the temperature, and the degree of fluorination desired withinthe pre-reactor. Slower feed rates at a given temperature will increasecontact time and tend to increase the amount of conversion of thestarting material and increase the degree of fluorination of theproducts.

The term “degree of fluorination” means the extent to which fluorineatoms replace chlorine substituents in the CX₃CCl═CClX (startingmaterials. For example, CF₃CCl═CClF represents a higher degree offluorination than CClF₂CCl═CCl₂ and CF₃CCl₂CF₃ represents a higherdegree of fluorination than CClF₂CCl₂CF₃.

The molar ratio of HF fed to the pre-reactor, or otherwise to thereaction zone of step (a), to halopropene starting material fed in step(a), is typically from about stoichiometric to about 50:1. Thestoichiometric ratio depends on the average degree of fluorination ofthe halopropene starting material(s) and is typically based on formationof C₃Cl₃F₅. For example, if the halopropene is HCP, the stoichiometricratio of HF to HCP is 5:1; if the halopropene is CFC-1213xa, thestoichiometric ratio of HF to CFC-1213xa is 2:1. Preferably, the molarratio of HF to halopropene starting material is from about twice thestoichiometric ratio (based on formation of C₃Cl₃F₅) to about 30:1.Higher ratios of HF to halopropene are not particularly beneficial.Lower ratios result in reduced yields of C₃Cl₃F₅ isomers.

If the halopropene starting materials are contacted with HF in apre-reactor, the effluent from the pre-reactor is then contacted withchlorine in the presence of a chlorofluorination catalyst.

In another embodiment of step (a), the halopropene starting material(s)may be contacted with Cl₂ and HF in a pre-reactor. The pre-reactor maybe empty (i.e., unpacked) but is preferably filled with a suitablepacking such as Monel™ or Hastelloy™ nickel alloy turnings or wool,activated carbon, or other material inert to HCl, HF, and Cl₂ whichallows efficient mixing of CX₃CCl═CClX, HF, and Cl₂.

Typically at least a portion of the halopropene starting material(s)react(s) with Cl₂ and HF in the pre-reactor by addition of Cl₂ to theolefinic bond to give a saturated halopropane as well as by subsitutionof at least a portion of the Cl substituents in the halopropropaneand/or halopropene by F. Suitable temperatures for the pre-reactor inthis embodiment of the invention are within the range of from about 80°C. to about 250° C., preferably from about 100° C. to about 200° C.Higher temperatures result in greater conversion of the halopropene(s)entering the reactor to saturated products and greater degrees ofhalogenation and fluorination in the pre-reactor products.

The term “degree of halogenation” means the extent to which hydrogensubstituents in a halocarbon have been replaced by halogen and theextent to which carbon-carbon double bonds have been saturated withhalogen. For example, CF₃CCl₂CClF₂ has a higher degree of halogenationthan CF₃CCl═CCl₂. Also, CF₃CCl₂CClF₂ has a higher degree of halogenationthan CF₃CHClCClF₂. The molar ratio of Cl₂ to halopropene startingmaterial(s) is typically from about 1:1 to about 10:1, and is preferablyfrom about 1:1 to about 5:1. Feeding Cl₂ at less than a 1:1 ratio willresult in the presence of relatively large amounts of unsaturatedmaterials and hydrogen-containing side products in the reactor effluent.

In a preferred embodiment of step (a) the halopropene starting materialsare vaporized, preferably in the presence of HF, and contacted with HFand Cl₂ in a pre-reactor and then contacted with the chlorofluorinationcatalyst. If the preferred amounts of HF and Cl₂ are fed in thepre-reactor, additional HF and Cl₂ are not required when the effluentfrom the pre-reactor contacts the chlorofluorination catalyst.

Suitable temperatures for catalytic chlorofluorination of halopropenestarting material and/or their products formed in the pre-reactor arewithin the range of from about 200° C. to about 400° C., preferably fromabout 250° C. to about 350° C., depending on the desired conversion ofthe starting material and the activity of the catalyst. Reactortemperatures greater than about 350° C. may result in products having adegree of fluorination greater than five. In other words, at highertemperatures, substantial amounts of chloropropanes containing six ormore fluorine substituents (e.g., CF₃CCl₂CF₃ or CF₃CClFCClF₂) may beformed. Reactor temperature below about 240° C. may result in asubstantial yield of products with a degree of fluorination less thanfive (i.e., underfluorinates).

Suitable reactor pressures for vapor phase embodiments of this inventionmay be in the range of from about 1 to about 30 atmospheres. Reactorpressures of about 5 atmospheres to about 20 atmospheres may beadvantageously employed to facilitate separation of HCl from otherreaction products in step (b) of the process.

The chlorofluorination catalysts which are used in the process of thepresent invention are preferably compositions comprising ZnCr₂O₄ (zincchromite) and crystalline α-Cr₂O₃ (alpha chromium oxide) or compositionsobtained by treatment of said compositions comprising ZnCr₂O₄ (zincchromite) and α-Cr₂O₃ (alpha chromium oxide) with a fluorinating agent.The amount of zinc relative to the total of chromium and zinc in thesecompositions is preferably from about 1 atom % to about 25 atom %.

Of note are chromium-containing catalyst compositions comprising ZnCr₂O₄(zinc chromite) and crystalline α-chromium oxide wherein the ZnCr₂O₄contains between about 10 atom percent and 67 atom percent of thechromium in the composition and at least about 70 atom percent of thezinc in the composition, and wherein at least about 90 atom percent ofthe chromium present as chromium oxide in the composition is present asZnCr₂O₄ or crystalline α-chromium oxide. Also of note arechromium-containing catalyst compositions, prepared by treatment of suchcompositions comprising ZnCr₂O₄ and crystalline α-chromium oxide with afluorinating agent. Also of note are such chromium-containing catalystcompositions which comprise ZnCr₂O₄ and crystalline α-chromium oxidewherein the ZnCr₂O₄ contains between about 20 atom percent and about 50atom percent of the chromium in the composition. Also of note are suchchromium-containing catalyst compositions which comprise ZnCr₂O₄ andcrystalline α-chromium oxide wherein the ZnCr₂O₄ contains at least about90 atom percent of the zinc in the composition. Also of note are suchchromium-containing catalyst compositions comprising zinc chromite andcrystalline α-chromium oxide wherein greater than 95 atom percent of thechromium that is not present as zinc chromite is present as crystallineα-chromium oxide. Also of note are such chromium-containing catalystcompositions which consist essentially of ZnCr₂O₄ (zinc chromite) andcrystalline α-chromium oxide.

These compositions may be prepared, for example, by co-precipitationmethods followed by calcination.

In a typical co-precipitation procedure, an aqueous solution of zinc andchromium(III) salts is prepared. The relative concentrations of the zincand chromium(III) salts in the aqueous solution is dictated by the bulkatom percent zinc relative to chromium desired in the final catalyst.Therefore, the concentration of zinc in the aqueous solution is fromabout 1 mole % to about 25 mole % of the total concentration of zinc andchromium in the solution. The concentration of chromium (III) in theaqueous solution is typically in the range of 0.3 to 3 moles per literwith 0.75-1.5 moles per liter being a preferred concentration. Whiledifferent chromium (III) salts might be employed, chromium(III) nitrateor its hydrated forms such as [Cr(NO₃)₃(H₂O)₉], are the most preferredchromium(III) salts for preparation of said aqueous solution.

While different zinc salts might be employed for preparation of saidaqueous solutions, preferred zinc salts for preparation of catalysts forthe process of this invention include zinc(II) nitrate and its hydratedforms such as [Zn(NO₃)₂(H₂O)₆].

The aqueous solution of the chromium (III) and zinc salts may then beevaporated either under vacuum or at elevated temperature to give asolid which is then calcined.

It is preferred to treat the aqueous solution of the chromium(III) andzinc salts with a base such as ammonium hydroxide (aqueous ammonia) toprecipitate the zinc and chromium as the hydroxides. Bases containingalkali metals such as sodium or potassium hydroxide or the carbonatesmay be used but are not preferred. The addition of ammonium hydroxide tothe aqueous solution of the chromium(III) and zinc salts is typicallycarried out gradually over a period of 1 to 12 hours. The pH of thesolution is monitored during the addition of base. The final pH istypically in the range of 6.0 to 11.0, preferably from about 7.5 toabout 9.0, most preferably about 8.0 to about 8.7. The precipitation ofthe zinc and chromium hydroxide mixture is typically carried out at atemperature of about 15° C. to about 60° C., preferably from about 20°C. to about 40° C. After the ammonium hydroxide is added, the mixture istypically stirred for up to 24 hours. The precipitated chromium and zinchydroxides serve as precursors to ZnCr₂O₄ and α-chromium oxide.

After the precipitation of the zinc and chromium hydroxide mixture iscomplete, the mixture is dried by evaporation. This may be carried outby heating the mixture in an open pan on a hot plate or steam bath or inan oven or furnace at a suitable temperature. Suitable temperaturesinclude temperatures from about 60° C. to about 130° C. (for example,about 100° C. to about 120° C.). Alternatively the drying step may becarried out under vacuum using, for example, a rotary evaporator.

Optionally, the precipitated zinc and chromium hydroxide mixture may becollected and, if desired, washed with deionized water before drying.Preferably the precipitated zinc and chromium hydroxide mixture is notwashed prior to the drying step.

After the zinc and chromium hydroxide mixture has been dried, thenitrate salts are then decomposed by heating the solid from about 250°C. to about 350° C. The resulting solid is then calcined at temperaturesof from about 400° C. to about 1000° C., preferably from about 400° C.to about 900° C.

Further information on the zinc and chromium compositions useful forthis invention is provided in U.S. patent application Ser. No.60/511,353 [CL2244 US PRV] filed Oct. 14, 2003, and hereby incorporatedby reference herein in its entirety (see also correspondingInternational Application No. PCT/US2004/______).

The calcined zinc chromite/α-chromium oxide compositions of the presentinvention may be pressed into various shapes such as pellets for use inpacking reactors. It may also be used in powder form.

Typically, the calcined compositions will be pre-treated with afluorinating agent prior to use as catalysts for changing the fluorinecontent of halogenated carbon compounds. Typically this fluorinatingagent is HF though other materials may be used such as sulfurtetrafluoride, carbonyl fluoride, and fluorinated carbon compounds suchas trichlorofluoromethane, dichlorodifluoromethane,chlorodifluoromethane, trifluoromethane, or1,1,2-trichlorotrifluoroethane. This pretreatment can be accomplished,for example, by placing the catalyst in a suitable container which canbe the reactor to be used to perform the process in the instantinvention, and thereafter, passing HF over the dried, calcined catalystso as to partially saturate the catalyst with HF. This is convenientlycarried out by passing HF over the catalyst for a period of time, forexample, about 0.1 to about 10 hours at a temperature of, for example,about 200° C. to about 450° C. Nevertheless, this pretreatment is notessential.

Other catalysts suitable for the chlorofluorinations of step (a) arecompositions comprising a zinc halide and α-chromium oxide andcompositions obtained by treatment of said compositions comprising azinc halide and α-chromium oxide with a fluorinating agent. U.S. Pat.No. 3,878,257 discloses an example of such catalysts. The amount of zincrelative to the total of chromium and zinc in these compositions ispreferably from about 0.1 atom % to about 25 atom %; and is morepreferably from about 2 atom % to about 10 atom %. Of note arecompositions wherein a zinc halide is supported on a support comprisingα-chromium oxide. Preferably, the α-chromium oxide is prepared accordingto U.S. Pat. No. 5,036,036. Pretreatment with a fluorinating agent canbe carried out as indicated above for the calcined zincchromite/α-chromium oxide compositions.

Compounds that are produced in the chlorofluorination process in step(a) include the halopropanes CF₃CCl₂CClF₂ (CFC-215aa) and CF₃CClFCCl₂F(CFC-215bb).

Halopropane by-products that have a higher degree of fluorination thanCFC-215aa and CFC-215bb that may be produced in step (a) includeCF₃CCl₂CF₃ (CFC-216aa), CF₃CClFCClF₂ (CFC-216ba), CF₃CF₂CCl₂F(CFC-216cb), CF₃CClFCF₃ (CFC-217ba), and CF₃CHClCF₃ (HCFC-226da).

Halopropane by-products that may be formed in step (a) which have lowerdegrees of fluorination than CFC-215aa and CFC-215bb includeCF₃CCl₂CCl₂F (HCFC-214ab).

Halopropene by-products that may be formed in step (a) includeCF₃CCl═CF₂ (CFC-1215xc), E- and Z-CF₃CCl═CClF (CFC-1214xb), andCF₃CCl═CCl₂ (CFC-1213xa).

Typically the effluent from step (a) comprising CF₃CCl₂CClF₂ (CFC-215aa)and CF₃CClFCCl₂F (CFC-215bb), and optionally HF, is separated from lowerboiling components comprising HCl, Cl₂, HF, over-fluorinated productscomprising C₃ClF₇ and C₃Cl₂F₆ isomers, the under-halogenated componentscomprising C₃CIF₅ and C₃Cl₂F₄ isomers, and the under-fluorinatedcomponents comprising C₃Cl₄F₄ isomers and CFC-1213xa.

In one embodiment of the invention the reactor effluent from step (a)may be delivered to a distillation column in which HCl and any HClazeotropes are removed from the top of column while the higher boilingcomponents are removed at the bottom of the column. The productsrecovered at the bottom of the first distillation column are thendelivered to a second distillation column in which HF, Cl₂, CF₃CCl₂CF₃(CFC-216aa), CF₃CClFCClF₂ (CFC-216ba), CF₃CF₂CCl₂F (CFC-216cb),CF₃CClFCF₃ (CFC-217ba), and CF₃CHClCF₃ (HCFC-226da) and their HFazeotropes are recovered at the top of the column and CFC-215aa andCFC-215bb, and any remaining HF and the higher boiling components areremoved from the bottom of the column. The products recovered from thebottom of the second distillation column may then be delivered to afurther distillation columns to separate the under-fluorinatedby-products and intermediates and to isolate CFC-215aa and CFC-215bb.

Optionally, after distillation and separation of HCl from the reactoreffluent of step (a), the resulting mixture of HF and halopropanes andhalopropenes may be delivered to a decanter controlled at a suitabletemperature to permit separation of a liquid HF-rich phase and a liquidorganic-rich phase. The organic-rich phase may then be distilled toisolate the CFC-215aa and CFC-215bb. The HF-rich phase may then berecycled to the reactor of step (a), optionally after removal of anyorganic components by distillation. The decantation step may be used atother points in the CFC-215aa/CFC-215bb separation scheme where HF ispresent.

In one embodiment of the present invention said underfluorinated andunderhalogenated components (e.g., CFC-214ab, CFC-1212xb, andCFC-1213xa) are returned to step (a).

In another embodiment of the present invention, the CFC-216aa, CFC-216baand HCFC-226da by-products are further reacted with HF, or if HCFC-226dais present, HF and Cl₂, to give CF₃CClFCF₃ (CFC-217ba) which in turn maybe converted to hexafluoropropene (HFP) as disclosed in U.S. Pat. Nos.5,068,472 and 5,057,634.

In another embodiment of the present invention, the HCFC-226da,CFC-216aa, CFC-216ba, CFC-217ba, and by-products are further reactedwith hydrogen (H₂) to give 1,1,1,3,3,3-hexafluoropropane (HFC-236fa),1,1,1,2,3,3-hexafluoropropane (HFC-236ea), and1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) as disclosed in U.S. patentapplication Ser. No. 60/511,355 [CL2246 US PRV] filed Oct. 14, 2003 (seealso corresponding International Application No. PCT/US2004/______).

In step (b) of the process of this invention, CF₃CCl₂CClF₂ (CFC-215aa)and CF₃CClFCCl₂F (CFC-215bb) produced in step (a) are reacted withhydrogen (H₂), optionally in the presence of HF.

In one embodiment of step (b), a mixture comprising CFC-215aa andCFC-215bb is delivered in the vapor phase, along with hydrogen (H₂), andoptionally HF, to a reactor fabricated from nickel, iron, titanium, ortheir alloys, as described in U.S. Pat. No. 6,540,933; the teachings ofthis disclosure are incorporated herein by reference. A reaction vesselof these materials (e.g., a metal tube) optionally packed with the metalin suitable form may also be used. When reference is made to alloys, itis meant a nickel alloy containing form 1 to 99.9% (by weight) nickel,an iron alloy containing 0.2 to 99.8% (by weight) iron, and a titaniumalloy containing 72-99.8% (by weight) titanium. Of note is use of anempty (i.e., unpacked) reaction vessel made of nickel or alloys ofnickel such as those containing 40% to 80% nickel, e.g., Inconel™ 600nickel alloy, Hastelloy™ C617 nickel alloy, or Hastelloy™ C276 nickelalloy.

When used for packing, the metal or metal alloys may be particles orformed shapes such as perforated plates, rings, wire, screen, chips,pipe, shot, gauze, or wool.

The temperature of the reaction in this embodiment can be between about350° C. and about 600° C., and is preferably at least about 450° C.

The molar ratio of hydrogen to the CFC-215aa/CFC-215bb mixture fed tothe reaction zone should be in the range of about 0.1 mole H₂ per moleof CFC-215 isomer to about 60 moles of H₂ per mole of CFC-215 isomer,more preferably from about 0.4 to 10 moles of H₂ per mole of CFC-215isomer.

In another embodiment of step (b), the contacting of hydrogen withCFC-215aa and CFC-215bb produced in step (a), and optionally HF, iscarried out in the presence of a hydrogenation catalyst. Hydrogenationcatalysts suitable for use in this embodiment include catalystscomprising at least one metal selected from the group consisting ofrhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel,palladium, and platinum. Said catalytic metal component is typicallysupported on a carrier such as carbon or graphite or a metal oxide,fluorinated metal oxide, or metal fluoride where the carrier metal isselected from the group consisting of magnesium, aluminum, titanium,vanadium, chromium, iron, and lanthanum. Of note are carbon supportedcatalysts in which the carbon support has been washed with acid and hasan ash content below about 0.1% by weight. Hydrogenation catalystssupported on low ash carbon are described in U.S. Pat. No. 5,136,113,the teachings of which are incorporated herein by reference.

The supported metal catalysts may be prepared by conventional methodsknown in the art such as by impregnation of the carrier with a solublesalt of the catalytic metal (e.g., palladium chloride or rhodiumnitrate) as described by Satterfield on page 95 of HeterogenousCatalysis in Industral Practice, 2nd edition (McGraw-Hill, New York,1991). The concentration of the catalytic metal(s) on the support istypically in the range of about 0.1% by weight of the catalyst to about5% by weight.

The relative amount of hydrogen contacted with CFC-215aa and CFC-215bbin the presence of a hydrogenation catalyst is typically from about 0.5mole of H₂ per mole of trichloropentafluoropropane isomer to about 10moles of H₂ per mole of trichloropentafluoropropane isomer, preferablyfrom about 3 moles of H₂ per mole of trichloropentafluoropropane isomerto about 8 moles of H₂ per mole of trichloropentafluoropropane isomer.

Suitable temperatures for the catalytic hydrogenation are typically inthe range of from about 100° C. to about 350° C., preferably from about125° C. to about 300° C. Temperatures above about 350° C. tend to resultin defluorination side reactions; temperatures below about 125° C. willresult in incomplete substitution of Cl for H in the C₃Cl₃F₅ startingmaterials.

The reactions are typically conducted at atmospheric pressure orsuperatmospheric pressure.

The effluent from the step (b) reaction zone typically includes HCl,unreacted hydrogen, CF₃CH₂CHF₂ (HFC-245fa), CF₃CHFCH₂F (HFC-245eb),lower boiling by-products (typically including CF₃CH═CF₂ (HFC-1225zc),E- and Z-CF₃CH═CHF (HFC-1234ze), CF₃CF═CH₂ (HFC-1234yf), CF₃CH₂CF₃(HFC-236fa), CF₃CHFCH₃ (HFC-254eb), and/or CF₃CH₂CH₃ (HFC-263fb)) andhigher boiling by-products and intermediates (typically includingCF₃CH₂CH₂Cl (HCFC-253fb), CF₃CHFCH₂Cl (HCFC-244eb), CF₃CClFCH₂F(HCFC-235bb), CF₃CHClCHF₂ (HCFC-235da), CF₃CHClCClF₂ (HCFC-225da),and/or CF₃CClFCHClF (HCFC-225ba diastereromers)) as well as any HFcarried over from step (a) or step (b).

In step (c), the desired products are recovered. The reactor productsfrom step (b) may be delivered to a separation unit to recoverCF₃CH₂CHF₂ and CF₃CHFCH₂F, individually or as a mixture.

Partially chlorinated components such as HCFC-235da, HCFC-235bb,HCFC-225ba, and HCFC-225da may also be recovered and recycled back tostep (b).

The reactor, distillation columns, and their associated feed lines,effluent lines, and associated units used in applying the processes ofthis invention should be constructed of materials resistant to hydrogenfluoride and hydrogen chloride. Typical materials of construction,well-known to the fluorination art, include stainless steels, inparticular of the austenitic type, the well-known high nickel alloys,such as Monel™ nickel-copper alloys, Hastelloy™ nickel-based alloys and,Inconel™ nickel-chromium alloys, and copper-clad steel.

The following specific embodiments are to be construed as merelyillustrative, and do not constrain the remainder of the disclosure inany way whatsoever.

EXAMPLES

LEGEND 214ab is CF₃CCl₂CCl₂F 215aa is CF₃CCl₂CClF₂ 215bb is CCl₂FCClFCF₃216aa is CF₃CCl₂CF₃ 216ba is CClF₂CClFCF₃ 217ba is CF₃CClFCF₃ 225ba isCF₃CClFCHClF 225da is CF₃CHClCClF₂ 226da is CF₃CHClCF₃ 235bb isCF₃CClFCH₂F 235 is C₃H₂ClF₅ 235da is CF₃CHClCHF₂ 235fa is CF₃CH₂CClF₂236fa is CF₃CH₂CF₃ 245eb is CF₃CHFCH₂F 245fa is CF₃CH₂CHF₂ 254eb isCF₃CHFCH₃ 263fb is CF₃CH₂CH₃ 1213xa is CF₃CCl═CCl₂ 1215xc is CF₃CCl═CF₂1224 is C₃HClF₄ 1225zc is CF₃CH═CF₂

Catalyst Preparation Comparative Preparation Example 1 Preparation of100% Chromium Catalyst (400° C.)

A solution of 400 g Cr(NO₃)₃[9(H₂O)] (1.0 mole) in 1000 mL of deionizedwater was treated dropwise with 477 mL of 7.4M aqueous ammonia raisingthe pH to about 8.5. The slurry was stirred at room temperatureovernight. After re-adjusting the pH to 8.5 with ammonia, the mixturewas poured into evaporating dishes and dried in air at 120° C. The driedsolid was then calcined in air at 400° C.; the resulting solid weighed61.15 g. The catalyst was pelletized (−12 to +20 mesh (1.68 to 0.84 mm))and 28.2 g (20 mL) was used in Comparative Example 3.

Comparative Preparation Example 2 Preparation of 2% Zinc on AluminaCatalyst

Aluminum oxide (4.90 moles, Harshaw 3945, dried at 110° C.) was added toa solution of 20.85 g ZnCl₂ (0.153 mole) dissolved in 460 mL ofdistilled water. Water was evaporated from the mixture with stirring andthen dried at 110° C. for three days. The catalyst was pelletized (−12to +20 mesh (1.68 to 0.84 mm)) and 21.1 g (30 mL) was used inComparative Example 1.

Preparation Example 1 Preparation of 2% Zinc chloride supported onChromium oxide

A solution of 1.20 g ZnCl₂ (8.81 mmoles) in 60 mL of deionized watercontained in a 125 mm×65 mm glass dish was treated with 60.00 g (0.357mole) of 12-20 mesh Cr₂O₃. The dish was placed on a warm hot plate andthe slurry allowed to dry with occasional stirring. The resulting solidwas then dried overnight at 130° C.; the resulting solid weighed 60.42g. The catalyst was pelletized (−12 to +20 mesh (1.68 to 0.84 mm)) and41.5 g (30 mL) was used in Example 9.

Preparation Example 2 Preparation of 95% Chromium/5% Zinc Catalyst (450°C.)

A solution of 380.14 g Cr(NO₃)₃[9(H₂O)] (0.950 mole) and 14.87 gZn(NO₃)₂[6(H₂O)] (0.050 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of one hour; the pH increased from 1.7 to pH8.4. The slurry was stirred at room temperature overnight and then driedat 120° C. in an oven in the presence of air. The dried solid was thencalcined in air at 450° C. for 20 hours; the resulting solid weighed76.72 g.

The catalyst was pelletized (−12 to +20 mesh (1.68 to 0.84 mm)) and 38.5g (25 mL) was used in Example 13.

Preparation Example 3 Preparation of 90% Chromium/10% Zinc Catalyst(900° C.)

A solution of 360.13 g Cr(NO₃)₃[9(H₂O)] (0.900 mole) and 29.75 gZn(NO₃)₂[6(H₂O)] (0.100 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of 1.4 hours; the pH increased from 1.9 to pH8.4. The slurry was stirred at room temperature overnight and then driedat 120° C. in the presence of air. The dried solid was then calcined inair at 900° C. for 20 hours; the resulting solid weighed 75.42 g. Thecatalyst was pelletized (−12 to +20 mesh (1.68 to 0.84 mm)) and 42.3 g(25 mL) was used in Examples 4, 5, and 6.

Preparation Example 4 Preparation of 95% Chromium/5% Zinc Catalyst (900°C.)

A solution of 380.14 g Cr(NO₃)₃[9(H₂O)] (0.950 mole) and 14.87 gZn(NO₃)₂[6(H₂O)] (0.050 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of one hour; the pH increased from 1.7 to pH8.4. The slurry was stirred at room temperature overnight and then driedat 120° C. in an oven in the presence of air. The dried solid was thencalcined in air at 900° C. for 20 hours; the resulting solid weighed70.06 g. The catalyst was pelletized (−12 to +20 mesh (1.68 to 0.84 mm))and 25.3 g (14 mL) was used in Examples 1 and 2.

Preparation Example 5 Preparation of 98% Chromium/2% Zinc Catalyst (900°C.)

A solution of 392.15 g Cr(NO₃)₃[9(H₂O)] (0.980 mole) and 5.94 gZn(NO₃)₂[6(H₂O)] (0.020 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of 0.58 hour; the pH increased from 1.67 to pH8.35. The slurry was stirred at room temperature overnight and thendried at 120° C. in an oven in the presence of air. The dried solid wasthen calcined in air at 900° C. for 21 hours; the resulting solidweighed 66.00 g. The catalyst was pelletized (−12 to +20 mesh (1.68 to0.84 mm)) and 44.9 g (23 mL) was used in Examples 7 and 8.

Preparation Example 6 Preparation of 10% Zinc chloride supported onChromium oxide

A solution of 6.0 g ZnCl₂ (44 mmoles) in 300 mL of deionized watercontained in a 170 mm×90 mm glass dish was treated with 60.00 g (0.357mole) of 12-20 mesh Cr₂O₃. The dish was placed on a warm hot plate andthe slurry allowed to dry with occasional stirring. The resulting solidwas then dried overnight at 130° C.; the resulting solid weighed 65.02g. The catalyst was pelletized (−12 to +20 mesh (1.68 to 0.84 mm)) and37.5 g (25 mL) was used in Examples 10 and 11.

Preparation Example 7 Preparation of 98.1% Chromium/1.9% Zinc Catalyst(550° C.)

A solution of 516.46 g Cr(NO₃)₃[9(H₂O)] (1.29 moles) and 7.31 gZn(NO₃)₂[6(H₂O)] (0.0246 mole) was prepared in 500 mL of distilled waterin 1 L beaker resting on a hot plate. The mixture was then transferredto a Pyrex™ container and the container placed in a furnace. Thecontainer was heated from room temperature to 125° C. at 10° C./min andthen held at 125° C. for six hours. The container was heated from 125°C. to 350° C. at 1° C./min and then held at 350° C. for six hours. Thecontainer was heated from 350° C. to 550° C. at 1° C./min and then heldat 550° C. for 24 hours. The catalyst was pelletized (−12 to +20 mesh(1.68 to 0.84 mm)) and 29.9 g (20 mL) was used in Example 12.

Preparation Example 8 Preparation of 80% Chromium/20% Zinc Catalyst(900° C.)

A solution of 320.12 g of Cr(NO₃)₃[9(H₂O)] (0.800 mole) and 59.49 gZn(NO₃)₂[6(H₂O)] (0.200 mole) was prepared in 1000 mL of deionizedwater. The solution was treated with 450 mL of 7.4M aqueous ammoniumhydroxide over the course of one hour; the pH increased from about 1.7to about pH 8.4. The slurry was stirred at room temperature overnightand then dried at 120° C. in an oven in the presence of air. The driedsolid was then calcined in air at 900° C. for 22 hours; the resultingsolid weighed 75.80 g. The catalyst was pelletized (−12 to +20 mesh,(1.68 to 0.84 mm)) and 41.7 g (25 mL) was used in Example 3.

Examples 1-13 and Comparative Examples 14 General Procedure forChlorofluorination

A weighed quantity of pelletized catalyst was placed in a ⅝″ (1.58 cm)diameter Inconel™ nickel alloy reactor tube heated in a fluidized sandbath. The tube was heated from 50° C. to 175° C. in a flow of nitrogen(50 cc/min; 8.3(10)⁻⁷ m³/sec) over the course of about one hour. HF wasthen admitted to the reactor at a flow rate of 50 cc/min (8.3(10)⁻⁷m³/sec). After 0.5 to 2 hours the nitrogen flow was decreased to 20cc/min (3.3(10)⁻⁷ m³/sec) and the HF flow increased to 80 cc/min(1.3(10)⁻⁶m³/sec); this flow was maintained for about 1 hour. Thereactor temperature was then gradually increased to 400° C. over 3 to 5hours. At the end of this period, the HF flow was stopped and thereactor cooled to 300° C. under 20 sccm (3.3(10)⁻⁷m³sec) nitrogen flow.CFC-1213xa was fed from a pump to a vaporizer maintained at about 118°C. The CFC-1213xa vapor was combined with the appropriate molar ratiosof HF and Cl₂ in a 0.5 inch (1.27 cm) diameter Monel™ nickel alloy tubepacked with Monel™ turnings. The mixture of reactants then entered thereactor; the contact time was 30 seconds unless otherwise indicated. Allreactions were conducted at a nominal pressure of one atmosphere. Theresults of CFC-1213xa chlorofluorination over the several catalysts areshown in Table 1; analytical data is given in units of GC area %.

Examples 14-17 Hydrodechlorination of CF₃CCl₂CClF₂

The results of the hydrodechlorination of a mixture of CF₃CCl₂CClF₂ overa 0.5% Pd supported on carbon catalyst are shown in Table 2. The productanalytical data is given in units of GC area %. The nominal catalyst bedvolume was 15 mL; the contact time was 30 seconds. Prior to beginningthe hydrodechlorination, the catalyst was reduced in a stream ofhydrogen at 300° C.

Examples 18-19 Hydrodechlorination of CF₃CClFCCl₂F

The results of the hydrodechlorination of CF₃CClFCCl₂F over the 0.5% Pdon carbon catalyst used in Examples 14-17 are shown in Table 3. Theproduct analytical data is given in units of GC area percent. TABLE 1EX. NO. HF:1213:Cl₂ T° C. Cat. 1215xc 217ba 226da 216aa 216ba 215aa215bb 214ab 1 30:1:10 280 Cr/Zn 95/5 900° C. 0.03 4.7 0.1 7.2 13.1 42.627.1 3.3 2 30:1:10 320 Cr/Zn 95/5 900° C. 0.05 7.5 0.2 16.2 18.4 33.521.7 0.5 3 20:1:4 280 Cr/Zn 80/20 900° C. 1.6 0.3 0.4 11.0 10.5 34.838.6 1.0 4 20:1:4 280 Cr/Zn 90/10 900° C. 0.3 0.4 0.8 15.5 4.3 53.1 30.24.0 5 20:1:4 300 Cr/Zn 90/10 900° C. 0.3 0.6 1.0 21.8 8.6 52.4 13.8 0.26 30:1:10 300 Cr/Zn 90/10 900° C. 0.1 0.8 0.5 16.9 10.3 54.9 15.2 0.2 720:1:4 280 Cr/Zn 98/2 900° C. 0.2 3.7 0.7 15.3 2.7 41.2 16.8 18.0 820:1:4 330 Cr/Zn 98/2 900° C. 0.1 11.2 0.5 28.0 22.7 28.9 6.6 0.03 920:1:4 260 Cr/ZnCl₂ 2% 0.6 0.9 0.8 9.0 3.7 75.9 7.3 0.8 10 20:1:4 280Cr/ZnCl₂ 10% — — — 4.7 — 24.9 18.3 50.8 11 20:1:4 320 Cr/ZnCl₂ 10% 0.30.2 0.1 10.8 3.9 47.4 26.0 9.5 12^(a) 20:1:4 300 Cr/Zn 98/2 550° C. 1.66.8 1.3 24.1 10.2 39.2 14.8 0.5 13 20:1:4 280 Cr/Zn 95/5 450° C. 0.3 0.11.8 10.2 3.4 77.7 5.0 0.3 Comp. 20:1:4 280 Zn/Al₂O₃ 0.5 — 29.1 4.0 0.365.3 — 0.05 Ex. 1 Comp. 20:1:4 300 Cr₂O₃ 900° C. 0.6 5.9 0.3 22.5 15.426.8 25.8 0.2 Ex. 2^(c) Comp. 20:1:4 320 Cr₂O₃ 0.2 12.4 2.4 30.3 18.034.5 — 0.02 Ex. 3^(a) Comp. 20:1:4 300 Cr₂O₃ HSA 0.9 0.1 11.7 25.9 1.659.2 — — Ex. 4^(d)^(a)The contact time was 15 seconds.^(b)The contact time was 5 seconds.^(c)Catalyst prepared by pyrolysis of ammonium dichromate and calcinedat 900° C. (see U.S. Pat. No. 5,036,036). Pre-treated with HF accordingto the general procedure.^(d)High surface area chromium oxide obtained from a commercial source.Pre-treated with HF according to the general procedure.

TABLE 2 CH₄ C₂H₆ EX. NO. H₂:215aa T° C. C₃H₈ 226da 263fb 1225zc 236fa245fa 1215xc 235fa 235da 1224 225da 215aa 14 4:1 100 0.02 0.5 — 63.1 —9.5 3.9 0.3 4.8 0.3 16.6 0.05 15 6:1 175 0.02 0.4 — 0.4 — 90.3 0.01 3.45.3 — 0.08 — 16 6:1 225 0.03 0.03 0.2 — 0.2 97.2 0.01 1.9 — — — — 17 6:1275 0.07 — 1.1 0.1 0.2 95.8 0.01 1.5 — — — —

TABLE 3 EX. NO. H₂:215bb T° C. 226da 254eb 235 245eb 235bb 225ba 215bb18 6:1 175 0.2 8.5 1.2 82.3 5.8 2.0 — 19 61 225 0.6 10.7 1.4 87.2 0.10.1 —

1. A process for the manufacture of 1,1,1,3,3-pentafluoropropane and 1,1,1,2,3-pentafluoropropane, comprising: (a) reacting hydrogen fluoride, chlorine, and at least one halopropene of the formula CX₃CCl═CClX, wherein each X is independently selected from the group consisting of F and Cl, to produce a product comprising CF₃CCl₂CClF₂ and CF₃CClFCCl₂F, wherein said CF₃CCl₂CClF₂ and CF₃CClFCCl₂F are produced in the presence of a chlorofluorination catalyst comprising at least one composition selected from the group consisting of (i) compositions comprising ZnCr₂O₄ and crystalline α-chromium oxide, (ii) compositions comprising a zinc halide and α-chromium oxide and (iii) compositions of (i) or (ii) which have been treated with a fluorinating agent; (b) reacting CF₃CCl₂CClF₂ and CF₃CClFCCl₂F produced in (a) with hydrogen to produce a product comprising CF₃CH₂CHF₂ and CF₃CHFCH₂F; and (c) recovering CF₃CH₂CHF₂ and CF₃CHFCH₂F from the product produced in (b).
 2. The process of claim 1 wherein in (a) the catalyst is selected from the group consisting of (i) compositions comprising ZnCr₂O₄ and crystalline α-chromium oxide and (iii) compositions of (i) which have been treated with a fluorinating agent.
 3. The process of claim 2 wherein the amount of zinc relative to the total of chromium and zinc in the catalyst composition is from about 1 atom % to about 25 atom %.
 4. The process of claim 2 wherein the catalyst is selected from the group consisting of (i) compositions comprising ZnCr₂O₄ and crystalline α-chromium oxide wherein the ZnCr₂O₄ contains between about 10 atom percent and 67 atom percent of the chromium in the composition and at least about 70 atom percent of the zinc in the composition, and wherein at least about 90 atom percent of the chromium present as chromium oxide in the composition is present as ZnCr₂O₄ or crystalline α-chromium oxide and (iii) compositions of (i) which have been treated with a fluorinating agent.
 5. The process of claim 1 wherein in (a) the catalyst is selected from the group consisting of (ii) compositions comprising a zinc halide and α-chromium oxide and (iii) compositions of (ii) which have been treated with a fluorinating agent.
 6. The process of claim 5 wherein the amount of zinc relative to the total of chromium and zinc in the catalyst composition is from about 0.1 atom % to about 25 atom %.
 7. The process of claim 5 wherein the catalyst is selected from the group consisting of (ii) compositions wherein a zinc halide is supported on a support comprising α-chromium oxide and (iii) compositions of (ii) which have been treated with a fluorinating agent; and wherein the amount of zinc relative to the total of chromium and zinc in the catalyst composition is from about 2 atom % to about 10 atom %. 